Cellular Mechanisms of Vasoregulation by Volatile Anesthetics

描述（由申请人提供）：两孔域K+通道（k2p通道）代表吸入麻醉剂作用于神经元的靶点。少数关于血管床上K2P通道的报道来自肺动脉和肠系膜动脉。我们最近发现ATP刺激K+电流，该电流对主要的K+通道阻滞剂具有抗性，并且对pH和Zn敏感。此外，我们的初步数据表明，这种电流通过K2P通道，这些通道可能调节血管直径。这是一个新的发现，定位K2P通道作为大脑动脉吸入麻醉剂的潜在靶点。我们的总体工作假设是，挥发性麻醉剂激活血管肌细胞中的K2P通道，从而扩张动脉。吸入麻醉剂会激活K2P通道，这取决于它们打开的概率。结合电生理、药理学、成像和血管张力测量，我们将在以下具体目标中验证这一假设。目的1：研究阻断剂抵抗性k2p样电流在胸主动脉和大脑中动脉中的药理学作用。为此，我们提出通过药理学手段证明，阻滞剂在酸性和受刺激的碱性pH下抑制的抗性全细胞向外电流具有K+选择性，并由k2p样通道携带。1)已知的k2p通道阻滞剂是否能降低胸主动脉和大脑中动脉肌细胞泄漏K+电流的幅度？2)血管肌细胞中k2样通道的打开决定了静息膜电位的哪一部分？3) K2P通道阻滞剂对血管直径有何影响？特定目标2：确定吸入性麻醉剂如何激活k2p样通道以及吸入性麻醉剂对血管张力的影响？我们将结合电生理学、药理学和血管张力测量来回答以下问题：1)全麻是否会增加K2P通道电流的幅度？2)全麻激活K2P通道对血管直径有何影响？3)吸入麻醉剂能增强atp诱导的血管反应吗？这些研究结果将描述一种通过K2P通道调节血管张力的新信号通路。区域特异性K2P通道的药理学特征将导致新的针对性治疗高血压和中风，并将有利于全身麻醉。

DESCRIPTION (provided by applicant): Two-pore-domain K+channels (K2P-channels) represent targets for actions of inhalation anesthetics on neurons. The few reports characterizing K2P channels in vascular beds are from pulmonary and mesenteric arteries. We have recently found that ATP stimulates K+current that is resistant to major K+channel blockers and sensitive to pH and Zn. Furthermore, our preliminary data suggest that this current is through K2P channels and that these channels may regulate vessel diameter. This is a novel finding that positions K2P channels as potential targets of inhalation anesthetics in cerebral arteries. Our overall working hypothesis is that volatile anesthetics activate K2P channels in vascular myocytes and thereby dilate arteries. Inhalation anesthetics will activate K2P channels depending on their open probability. Using a combination of electrophysiological, pharmacological, imaging and vessel tension measurements, we will test this hypothesis in the following specific aims. Specific Aim 1: To determine pharmacology of blockers-resistive K2P-like currents in thoracic aorta and middle cerebral artery. In this aim, we propose to prove by pharmacological tools that blockers resistive whole cell outward current inhibited by acidic and stimulated basic pH has K+selectivity and is carried by K2P-like channels. 1) Do known K2P-channel blockers decrease amplitude of leak K+currents in myocytes isolated from thoracic aorta and middle cerebral artery? 2) What part of the resting membrane potential is determined by opening of K2P-like channels in vascular myocytes? 3) What is the impact of K2P channel blockers on vessel diameter? Specific Aim 2: To determine how inhalation anesthetics activate K2P-like channels and the impact of inhalation anesthetics on vascular tone? We will use a combination of electrophysiology, pharmacology, and vessel tension measurements to answer the questions: 1) Do general anesthetics increase the amplitude of K2P channel currents? 2) What is the impact of K2P channel activation by general anesthetics on vessel diameter? 3) Can inhalational anesthetics potentiate ATP-elicited vascular responses? The results of these studies will describe a novel signaling pathway regulating vascular tone through K2P channels. Pharmacological characterization of region specific K2P channels should lead to new targeted treatments of hypertension and stroke and will be of benefit for general anesthesia. PUBLIC HEALTH RELEVANCE: Cardiovascular disease, hypertension and stroke are leading causes of death in the U.S. The present proposal will investigate a novel signaling pathway to regulate vascular tone via K2P channels. Pharmacological characterization of region specific K2P channels (middle cerebral artery and aorta) should lead to new targeted treatments of hypertension and stroke. These types of studies will validate cellular mechanisms of anesthetic action and could be used to develop a possible treatment protocol.